The overall objective of this proposal is to continue the support at Vanderbilt University of an existing interdepartmental, multidisciplinary Reproductive Biology Research Center. The continuous support of the Center will maintain the efficiency of many population related projects now active at Vanderbilt and will permit development in a new area not presently represented. The research objectives of the Center include investigations on male reproductive physiology (sperm production, sperm biochemistry, sperm maturation, sperm capacitation, development of male contraception, and neuroendocrine control of male sexual behavior), on female reproductive physiology (fertilization and implantation), on reproductive endocrinology, and growth an differentiation. Support is requested for an Administrative Core unit and eight core facilities (Histology/Photomicroscopy, Electron Microscopy, Cell Culture/Growth Factors, Hormone Assay, Organic Chemistry/Prostaglandin, Protein Chemistry, Glycoprotein, and Molecular Biology) and two Program Developments (Molecular Analysis of XY Sex Reversal in the Mouse and Relation of Growth to Differentiation in the Mammotrope).